JP2005155694A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device 3 capable of maintaining excellent sealing performance by preventing a seal lip 33 from coming into contact with a mate member 21 fully. <P>SOLUTION: This sealing device 3 is provided with the seal lip (radial lip) 33 in which a seal edge part 33a at the inner periphery in a tip part which is fixed on a member (outer peripheral member) 1 on one side so as to seal is brought into close contact with a sleeve part 21a of the mate member (slinger) 21 rotatable relatively for the member 1 on one side slidably. A second edge part 33b brought into contact with the mate member 21 in a deformation condition exceeding a predetermined condition of the seal lip 33 is formed on an inner peripheral face on a basic part 34 side more than the seal edge part 33a in the seal lip 33. The second edge part 33b protrudes onto a mate member 21 side more than a virtual face A passing through an end part inner peripheral face 33d on the basic part 34 side and the seal edge part 33a. A recessed part 33c between the seal edge part 33a and the second edge part 33b is retracted more than the virtual face A. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sealing device used as a sealing means for a driving wheel bearing unit of a vehicle or a rotating part of a general-purpose machine.

As a conventional sealing device used for a bearing unit for a driving wheel of a vehicle or the like, for example, those described in Patent Documents 1 to 3 below are known.
JP 62-283261 A (FIG. 1) Japanese Patent Laid-Open No. 10-252762 (FIGS. 2 and 3 etc.) Japanese Patent Laying-Open No. 2003-246203 (FIG. 1)

  FIG. 4 is a half cross-sectional view showing a sealing device of the same type as that described in the above-mentioned patent document, cut along a plane passing through its axis. In FIG. 4, reference numeral 100 is an outer peripheral member (for example, an outer ring in Patent Document 2) of the bearing unit, and 110 is an inner peripheral member (for example, an inner ring in Patent Document 2). Between the inner peripheral surface of the outer peripheral member 100 and the outer peripheral surface of the inner peripheral member 110, it is possible to prevent foreign matter such as rainwater, muddy water, or dirt from entering the inner space S2 from the outer space S1 and the inner space. A sealing device 120 for preventing the grease filled in S2 from leaking to the outside is interposed.

  The sealing device 120 includes a metal outer ring 121 that is press-fitted to the inner peripheral surface of the outer peripheral member 100, and a side lip 122 and a radial lip 123 that are integrally provided on the outer ring 121. 122 and the radial lip 123 are slidably in close contact with the slinger 111 closely fitted to the inner peripheral member 110. Specifically, the side lip 122 and the radial lip 123 are made of a rubber-like elastic material, and are integrally vulcanized and bonded to the outer ring 121 through a common base 124. The side lip 122 extends so as to open to the side opposite to the internal space S2, and the tip thereof is slidably in contact with the end surface of the flange portion 111a of the slinger 111. The radial lip 123 on the inner peripheral side A seal edge portion 123a at the tip facing the space S1 side is in close contact with the outer peripheral surface of the inner peripheral cylindrical portion 111b of the slinger 111 so as to be slidable.

  This type of sealing device 120 is used under severe conditions in which rainwater or muddy water splashed from the road surface flows from the gap G between the flange portion 111a of the slinger 111 and the outer peripheral cylinder portion 121a of the outer ring 121. In order to improve the sealing performance, the surface pressure of the side lip 122 and the radial lip 123 with respect to the slinger 111 is increased. However, when the surface pressure of the radial lip 123 is increased, the radial distance between the outer circumferential member 100 and the inner circumferential member 110 is reduced if there is a relative eccentricity or mounting error between the outer circumferential member 100 and the inner circumferential member 110. On the side, the inner peripheral surface of the intermediate portion 123b between the seal edge portion 123a and the base portion 124 of the radial lip 123 is liable to stick to the outer peripheral surface of the inner peripheral cylindrical portion 111b of the slinger 111.

  In addition, this type of sealing device 120 has a small cross-section of about 5 mm in the axial direction and about 7 to 10 mm in the radial direction. Therefore, the side lip 122 and the radial lip 123 are also small and thin. For this reason, even a slight eccentricity or mounting error causes a solid contact of the radial lip 123, the sliding load becomes significantly large, and the sealing performance against muddy water or the like may be impaired at an early stage.

  Further, for example, when the gas in the internal space S2 contracts due to a temperature drop or the like, a negative pressure is generated in the internal space S2. In such a case as well, the radial lip 123 is caused by a pressure difference between both sides of the radial lip 123. In this case, the inner peripheral surface 123b on the base side of the seal edge portion 123a has a solid contact with the outer peripheral surface of the inner peripheral cylindrical portion 111b of the slinger 111, and the same problem as described above has occurred.

  The present invention has been made in view of the above problems, and its technical problem is to provide a sealing device that prevents the seal lip from sticking to the mating member and maintains excellent sealing performance. There is to do.

  As means for effectively solving the technical problem described above, the sealing device according to the invention of claim 1 is hermetically fixed to one member of two members that are arranged substantially concentrically and relatively rotate. A seal lip that is slidably brought into close contact with the other mating member, and a seal lip of the seal lip has an inner peripheral surface closer to the base than the seal edge portion, and the seal lip is more than a predetermined amount. A second edge portion that is in contact with the mating member in the deformed state is formed.

  According to a second aspect of the present invention, there is provided the sealing device according to the first aspect, wherein the second edge portion is on the counterpart member side with respect to a virtual surface passing through the inner peripheral surface of the end portion on the base side of the seal lip and the seal edge portion. The recessed part between the said seal edge part and the 2nd edge part has receded rather than the said virtual surface with respect to the said other member.

  According to the sealing device of the first aspect of the present invention, when the seal lip is subjected to the deformation more than the predetermined value, the second edge portion comes into contact with the other member. A decrease in sealing function due to an increase in dynamic load can be prevented.

  According to the sealing device of the second aspect of the invention, in addition to the effect of the first aspect, the deformation stress of the seal lip is relieved by the bending deformation of the constricted portion due to the concave portion, so that the increase in the surface pressure of the seal edge portion is effective. By being relaxed, it is possible to prevent the sealing function from being lowered due to an increase in sliding load.

  Hereinafter, preferred embodiments of a sealing device according to the present invention will be described with reference to the drawings. FIG. 1 is a half sectional view showing a sealing device 3 according to an embodiment of the present invention by cutting along a plane passing through its axis, and FIG. 2 is a portion showing a radial lip in the sealing device in FIG. FIG. 3 is a half sectional view showing a state in which the radial lip in the sealing device of FIG. 1 is deformed by eccentricity.

  In FIG. 1, reference numeral 1 is an outer peripheral member such as a bearing unit and corresponds to “one member” recited in claim 1, and reference numeral 2 is substantially concentric with the inner periphery of the outer peripheral member 1. In addition, an inner peripheral member such as a bearing unit that is rotatably supported, and reference numeral 3 is a sealing device of the present invention interposed between the outer peripheral member 1 and the inner peripheral member 2.

  In the sealing device 3, foreign matter such as rainwater, muddy water, or dirt enters the internal space S2 from the outer space S1 on the right side in FIG. 1 between the outer peripheral member 1 and the inner peripheral member 2 into the inner space S2 on the left side. It prevents the filled grease from leaking into the external space S1, and includes an outer ring 31 that is tightly fitted and fixed to the outer peripheral member 1, and a side lip 32 and a radial lip 33 that are provided integrally with the outer ring 31. And the distal ends of the side lip 32 and the radial lip 33 are slidably in close contact with the slinger 21 that is tightly fitted and fixed to the inner peripheral member 2. The radial lip 33 corresponds to the “seal lip” recited in claim 1, and the slinger 21 corresponds to the “counter member” recited in claim 1.

  The outer ring 31 is formed by stamping and pressing a metal plate such as a steel plate, and is provided with an outer peripheral cylindrical portion 31a that is press-fitted with a predetermined tightening margin into the inner peripheral surface 1a of the outer peripheral member 1 and tightly fitted therein, and its inner space S2. It consists of the inward flange part 31b extended to the inner peripheral side from the end which becomes a side. The side lip 32 and the radial lip 33 are made of a rubber-like elastic material, and have a common base portion 34. The base portion 34 extends from the inner peripheral portion of the inward flange portion 31b of the outer ring 31 to the inside thereof. It extends so as to cover the inner peripheral surface of the outer peripheral cylindrical portion 31 a through the side surface, and is integrated with the outer ring 31.

  That is, the sealing device 3 positions and sets the outer ring 31 previously coated with a vulcanizing adhesive in a predetermined mold (not shown), and clamps the outer ring 31 between the outer ring 31 and the inner surface of the mold. The base 34 is integrated with the outer ring 31 simultaneously with the vulcanization molding of the side lip 32, the radial lip 33 and the base 34 by filling the formed annular cavity with unvulcanized rubber material and heating and pressurizing. Vulcanized and bonded.

  The slinger 21 is manufactured by punching and pressing a metal plate such as a steel plate, and has a sleeve portion 21a that is press-fitted in close contact with the outer peripheral surface 2a of the inner peripheral member 2 with a predetermined allowance, and an outer space S1 thereof. It consists of the outward flange part 21b expand | deployed in the planar shape orthogonal to an axial center from the edge part used as a side to the outer peripheral side. The outer diameter of the outward flange portion 21b is smaller than the inner peripheral surface of the rubber layer 34a (a part of the base portion 34) attached to the outer peripheral cylindrical portion 31a of the outer ring 31, and therefore an annular gap is formed between the two. G is formed.

  The side lip 32 is formed in a substantially conical cylindrical shape that extends from the position near the inner periphery of the base portion 34 toward the outer space S1 and is opened so that the tip has a relatively large diameter. The side lip 32 is appropriately bent and deformed with the outward flange portion 21b of the slinger 21, and the distal end portion 32a has a planar shape substantially perpendicular to the axial center. It is brought into close contact with the inner surface of the slidable member at an appropriate surface pressure.

  The radial lip 33 is located on the inner peripheral side of the side lip 32, protrudes from the inner peripheral portion of the base portion 34 toward the external space S1, and has a smaller diameter from the base portion 34 side toward the distal end portion side. It has a substantially conical cylindrical shape. The inner diameter of the seal edge portion 33a formed in a substantially V-shaped projecting shape on the inner periphery of the distal end of the radial lip 33 is smaller than the outer diameter of the sleeve portion 21a in the slinger 21 when not attached as shown in FIG. That is, in the mounted state shown in FIG. 1, the sleeve portion 21a is slidably brought into close contact with the outer peripheral surface of the sleeve portion 21a with an appropriate tightening margin.

  A second edge portion 33 b protruding in a substantially V shape is formed on the inner peripheral surface of the radial lip 33 closer to the base portion 34 than the seal edge portion 33 a. The second edge portion 33b has an inner diameter larger than the inner diameter of the seal edge portion 33a, and is normally not in contact with the sleeve portion 21a of the slinger 21, and as shown in FIG. In the deformed state, it comes into contact with the outer peripheral surface of the sleeve portion 21a.

  Further, as shown in FIG. 2, the second edge portion 33b is more than a virtual surface A (corresponding to the conventional shape) passing through the inner peripheral surface 33d on the base 34 side of the radial lip 33 and the seal edge portion 33a. A concave portion 33c that protrudes toward the inner peripheral side, i.e., the sleeve portion 21a side, recedes from the virtual plane A toward the outer peripheral side.

  As shown in FIG. 1, the sealing device 3 having the above configuration is hermetically fixed to the inner peripheral surface 1 a of the outer peripheral member 1 at the outer peripheral cylindrical portion 31 a of the outer ring 31, and the side lip 32 and the radial lip 33. Is slidably in close contact with the outward flange portion 21b and the sleeve portion 21a of the slinger 21 that rotate integrally with the inner peripheral member 2, so that dust, muddy water, and the like are transferred from the outer space S1 side to the inner space S2 side. Is to prevent inflow. Normally, as shown in FIG. 1, in the radial lip 33, only the seal edge portion 33a is in close contact with the outer peripheral surface of the sleeve portion 21a of the slinger 21 with a predetermined crushing margin, and the second edge portion 33b is in a non-contact state. It is in.

  Since the outward flange portion 21b of the slinger 21 gives a centrifugal force to the fluid in contact therewith, an attempt is made to intervene in the sliding portion between the side lip 32 and the outward flange portion 21b of the slinger 21 from the external space S1 side. Rainwater, muddy water, and the like are shaken off by the centrifugal force and removed to the outer peripheral side.

  Further, even if a slight amount of rain water, muddy water, or the like passes through the sliding portion between the distal end portion 32a of the side lip 32 and the outward flange portion 21b of the slinger 21 to the inner peripheral side, this rain water, muddy water, etc. Since sealing is performed at the sliding portion between the lip 33 and the sleeve portion 21a of the slinger 21, eventually, the sliding portion between the outward flange portion 21b and the side lip 32 is caused by the swinging action of the outward flange portion 21b. It is pushed back and discharged from the outer periphery to the external space S1 side.

  Here, the sealing device 3 has a small cross section shown in FIG. 1 of about 5 mm in the axial direction and about 7 to 10 mm in the radial direction, and the radial lip 33 is also small and thin. For example, when the outer peripheral member 1 and the inner peripheral member 2 are eccentric from each other due to an attachment error or the like, even if the amount of eccentricity is small, the outer side member 1 is outside on the side closer to the outer peripheral member 1. The radial lip 33 is greatly deformed in the radial direction between the base 34 bonded to the ring 31 and the sleeve portion 21 a of the slinger 21. For this reason, the intermediate portion 33e between the seal edge portion 33a and the base portion 34 of the radial lip 33 relatively approaches the sleeve portion 21a of the slinger 21.

  Further, for example, when the gas in the internal space S2 contracts due to a rapid temperature drop or the like, and a negative pressure is generated in the internal space S2, the radial lip 33 has a pressure equal to the atmospheric pressure of the external space S1. Due to the difference, the intermediate portion 33e approaches the sleeve portion 21a of the slinger 21 relatively.

  However, according to the sealing device 3 of the present invention, when the radial lip 33 is deformed more than a predetermined amount, as shown in FIG. 3, the second edge portion 33b contacts the outer peripheral surface of the sleeve portion 21a. It is possible to effectively prevent the inner peripheral surface of the intermediate portion 33e of the radial lip 33 from sticking to the outer peripheral surface of the sleeve portion 21a of the slinger 21 effectively. In addition, in this state, the recess 33c effectively suppresses an increase in the sliding area between the seal edge portion 33a and the second edge portion 33b.

  Further, as shown in FIG. 2, the second edge portion 33b protrudes to the inner peripheral side from the virtual surface A passing through the end inner peripheral surface 33d and the seal edge portion 33a on the base 34 side of the radial lip 33. Therefore, the portion where the second edge portion 33b is formed is relatively thick, and the recess between the seal edge portion 33a and the second edge portion 33b recedes from the virtual surface A to the outer peripheral side. It is constricted by 33c and is relatively thin. For this reason, when the radial lip 33 is deformed due to the eccentricity or the pressure difference as described above, it is easy to bend and deform at the constricted portion 33f due to the concave portion 33c, so the surface pressure of the seal edge portion 33a against the sleeve portion 21a of the slinger 21 increases. Is effectively mitigated.

  Accordingly, such an action prevents the radial lip 33 from sticking to the sleeve portion 21a of the slinger 21 and suppresses an increase in surface pressure, thereby preventing an early decline in sealing performance due to an increase in sliding load. can do.

  In the sealing device 3 according to the illustrated embodiment, the side lip 32 and the radial lip 33 are in intimate contact with the slinger 21 attached to the inner peripheral member 2, but in the present invention, the side lip 32 and the radial lip 33 are For example, the present invention can be applied to an end surface portion formed on the inner peripheral member 2 and a member that is in close contact with the cylindrical outer peripheral surface. In this case, the inner peripheral member 2 corresponds to the “partner member” described in claim 1.

1 is a half sectional view showing a sealing device according to an embodiment of the present invention by cutting along a plane passing through its axis. It is a fragmentary sectional view which shows the radial lip in the sealing device of FIG. FIG. 2 is a half cross-sectional view showing a state in which the radial lip in the sealing device of FIG. 1 is deformed by eccentricity. It is a half sectional view which cuts and shows the conventional sealing device by the plane which passes along the axis.

Explanation of symbols

1 Peripheral member (one member)
2 Inner peripheral member 21 Slinger (mating member)
21a Sleeve part 21b Outward flange part 3 Sealing device 31 Outer ring 31a Outer peripheral cylinder part 31b Inward flange part 32 Side lip 33 Radial lip (seal lip)
33a Seal edge portion 33b Second edge portion 33c Recess 33d End inner peripheral surface 33e Intermediate portion 33f Constricted portion 34 Base A Virtual surface S1 External space S2 Internal space

Claims (2)

  Sealingly fixed to one member (1) of the two members that are arranged substantially concentrically and rotate relative to each other so that the seal edge portion (33a) at the tip is slidable on the other mating member (21) A seal lip (33) to be in close contact is provided, and the seal lip (33) is deformed more than a predetermined amount on the inner peripheral surface of the seal lip (33) closer to the base (34) than the seal edge (33a). And a second edge portion (33b) in contact with the mating member (21).   The second edge portion (33b) is a counterpart member (21) rather than an imaginary surface (A) passing through the inner peripheral surface (33d) on the base portion (34) side of the seal lip (33) and the seal edge portion (33a). Projecting to the side, the recess (33c) between the seal edge portion (33a) and the second edge portion (33b) is retracted from the virtual surface (A) with respect to the counterpart member (21). The sealing device according to claim 1.

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